Do you know if there exist some method directly convert non-polarized infrared light into low THz,GHz or MHz waves with high efficiency?
I know there exist optical frequency converters,but they work usually as frequency
multipliers and used to convert infrared to ultraviolet.

I have never heard of such things. I dealt with microwave communications for a significant part of my life, and can think of examples of multipliers, but I know of none for dividers. If you are looking for a controllable high power, you can get a solid state frequency modulated microwave oscillator relatively cheap today, and amplify the power with a TWT.

I just thought about some energy conversion device which is able to convert infrared directly into GHz or THz and latest into electricity.I know that conversion efficiency of rectennas could reach 90%.Heterodyne technology seem to be existing although it's difficult to find what is efficiency of this process.In some place I found that quantum efficiency of frequency converters based on quantum wells could reach 90%.